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LED grow lights in a greenhouse

LEDs and greenhouses: expert advice for getting started

From seeking out partners to embracing experimentation, here’s how growers can get the most out of energy-efficient LED lighting.

Compared to high-pressure sodium (HPS) lighting – still the norm in many Ontario greenhouses – LED lighting is significantly more energy-efficient and can lower energy costs. 

LED grow lights can boost a greenhouse bottom line in more ways than one. In addition to reducing energy costs, LEDs can lead to better quality plants and higher yields. LEDs also have a longer lifespan, allowing growers to reduce their longer-term maintenance and labour costs.

Even with all of these benefits, upgrading to LEDs may seem overwhelming. With that in mind, we asked researchers in the field for their views on what greenhouse operators should consider when getting started.

Figure out your needs – and stay flexible

Planning is everything. Before investing in lighting upgrades, growers need to assess and align the goals for their operations beyond just saving energy. 

“Growers need to determine what they want to achieve with lighting,” says James Dyck, a researcher with the Ontario Ministry of Agriculture, Food and Rural Affairs. 

It may be improved plant quality, such as higher nutritional content, or a shorter production cycle. Depending on the desired outcome, the lighting setup – including number of lights, position and colour – may be different.  

LEDs are flexible, so growers can use them to promote more flowering, control pathogens and more. But it doesn’t have to be an all-or-nothing decision. “Different lighting systems can be combined to create a hybrid lighting system that gives growers options,” Dyck adds.

Take advantage of expert help

Many growers may not realize that researchers from Ontario universities and government ministries are on hand to help them assess their lighting needs. 

“Researchers routinely undertake work to help growers and to conduct their own research,” says Mike Dixon, a University of Guelph professor and researcher on controlled environments. This is not well-publicized, so growers may not know they can – and should – reach out to experts in specific fields to ask questions about getting the most out of their greenhouse LEDs.

“Ideally, you want the same light quality across the whole plant growing area, while attempting to homogenize other variables as much as possible, such as water and nutrients,” Dixon says. Experts can help growers determine appropriate spacing for their crops and the lighting to optimize results. 

Researchers may also have access to spectral radiometers to help measure available light and assess supplemental lighting needs. These tools are expensive, so partnering with a researcher may be better for a grower’s bottom line. 

“LED manufacturers have technicians and advisors who are able to assess grower needs,” Dixon adds. This includes assessing light intensity and spectral quality but also providing input on design choices, including creating a hybrid lighting system for the best possible results.

Think unconventionally

Growers can also act as their own “scientific advisors based on their extensive experience,” Dixon says. This can include small-scale trials to test how LEDs may have an impact on their crops, based on the research available. For example, they can try different LED colours on plants at different stages of growth. Collaborating with industry researchers could enable growers to leverage scientific research tax credits or grants, he points out.

Small-scale trials with LEDs also allow growers to experiment with new approaches, such as light positioning. “LEDs allow growers to do unconventional things to distribute light more homogenously. It’s worth investigating the use of LED light distribution from the bottom of a plant, from the side, or hanging from above,” Dixon says.

For example, you could try long strips of LEDs hanging down over plants, or place the lights very close to the plants if you want volume. If a plant is of low stature, you may be able to achieve high density with close lighting, he says. 

At the end of the day, getting started with greenhouse LEDs doesn’t have to be overwhelming. With some planning, expert help and a willingness to experiment, greenhouse operators can see positive results – and a growing bottom line.

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